Electrical resistance.



J. A. MISLAND.

ELECTRICAL RESISTANGE.

APPLICATION FILED MAY 23, 1910.

Patenteq Aug. 20, 1912.

on O T N E V N.

citizen of theUnited States,

, ence numeral. l.

' invention illustrated in. the. drawings the r nnrrnn STATES PATENT OFFICE;

' JOSEPH a. MILSIiAND, or BAYONNE, NEW ERSEY.

ELECTRICAL RESISTANCE.

To all whom, it may concern Be it known that LiJosnru A. MISLAND, reslding at Bayonne, county of Hudson, and State of New Jersey, have invented certain new and useful ll'nprovements,in Electrical Resistances; and I do hereby declare the "following to be a full, clear, and exact'description of the invention, such as will enable others skilled. in the art to which it appertains to make and use the same. l

The invention relates to electrical resistances,. or resistmice-elements, having the cl'iaracterist-ic that. the amount of resistance otl'ered to the flow of the electrical current may be varied without the employment of a slid ing or other moving contact or the breaking; of any circuit; z

The object of the invention is to provide a simple and durable resistance-element of this character, suitable for use in the widest variety of places, and under the mostsevere operating conditions.

"1. he nature of theinvention will be made fully apparent by the following description and the accompanying drawings.

In the drawings, Figurel represents one of my improved resistance-elements in elevation, and drawn out beyond the extreme position whichit will normally occupy in prac tice, for the purpose ofbetter illustration. Fig. 2 is a central. section, showing the resistance-element. in its closed or short-circuited position. Fig. 3 a plan view show in o, a section on the Hush-25 of Fig. 2.-

The resistance-clement composed of roiled uninsulatcd wire, 1 some alloy having a high specific resistance, such as (lerman silver. or some one of the other high resistance alloys which have more recently come into nse,,-f'l"his coiled' wire is represented in the drawings by the referit is attached at one end to a conducting: support-"J ol cop 'ier, brass, or the like, and at the other end to -n car rier it, the support and the carrierbeing relatively movable with respect to ouecanother sothat they may be separated todrawthe resistance \\'ireout\' of contact. with the conducting support, 'or broughttogether to lay the resistance wire in contact with the conducting support and thereby gradually short circuit the convolntions and correspondingly reduce the resistance ot the element. ln the prclerred embodiment of the n. ,t'erably made o't' conducting support is a frustum of'a cone Specification of Letters Iatent. Patented Aug -20, 1912, v Application filed ma 23, 1 10. Serial No. 562,883,

and the resistance wire is coiled intoa coni-- cal spiral which, in its closed position, as shown 1 n Fig. 2, conforms to the surface of the conical support and hes in contact with it. In this position ,the resistance wlre s" -substantially short circuited by the conducting support (or it may be completely shortcirculted by bringing the carrier 3 into close conducting contact with thesupport 2) Upon se 'iarating the support and carrier the coils of the resistance wire aresuccessively drawn away from the conducting support and the resistance gradually increased.

- and the resistance is reduced to a minimum.-

find that the rate'of increase of the resistanee as the carrier and support are moved apart may be varied by changing the Con,

trac tile. force of the convolutions. If the convolutions are tight, so that the coil tends to close itself upon the support, the se )aration of the coilfrom the support, an

the i consequent increase of resistance, willbe comparatively rapid; whereas if the convolutions are-such as to lie loosely upon the support the increase of resistance will be more gradual.

It will be observed thatin the drawings I have illustrated a coil in which the convolutions are so close together that when closed;

upon the support, as shown in Fig. 2-, they lie in contact with one another. This gives the maximum length of resistance wire for a support of given size, and an additional short-circuiting effect resulting, from such contact of the convolutions. In fact, with this arrangement it is notessential that the support should be of conducting material.

The short-circuiting contactot' the convolu-' tions'with one ttlOt'llQl' may then be relied upon to bring' 'alio'ut the gradual decrease of resistance up' 'the coil is closed. ()n the other.hand it 'is possible, as will be readily understood, to so coil-the resistance wire that the individual convolutionsdo. not lie in contact with one another when closed 'In' that case the support i upon the support. must be of conducting material to perform the short-circuiting function.

\Vith res:stance-element constructed in accordance with my invention, as above 'described, it is only necessary, in order to yary the resistance, to provide suitable mechanism, such for example, as a solenoid, for gradually drawing away the carrier 3 from the base, or the ba e,-fro.ui, t he carrier.

As will be understood by those skilled in the art, the resistance elements may be used alone or in any number, and they may be connected either in series or parallel, as the demands of the particular service required of them may suggest.

What I claim is:

l. A resistance element comprising a short circuitingconducting support, a coil of uninsulated conducting wire having one end fastened to said support, and a relatively movable carrier to which the other end of the coil is attached. 2. A resistance element comprising a short-circuiting conical conducting support, an uninsulated conducting wire coiled about said support in such manner that the individual convolutions may be brought into contact with the support, and a relatively movable terminal to which the other'end of the wire is attached.

3. A resistance element comprising a shortcircuiting conical conducting support, an uninsulated conducting wire coiled about said support in such manner that the individual convolutions may be brought into contact with one another and with the support, and a relatively movable carrier to which the other end of the wire is attached. 7

4. A resistance element comprising a conical support, an uninsulated conducting wire coiled about said support in such manner that the individual convolutions may be brought into contact with one another and with the support, anda relatively movable terminal to which the other end of the wire is attached.

In testimony whereof l' afiix my signature,

in presence of two witnesses.

I JOSEPH A. MISLAND.

Witnesses:

Tnos. L. Moun'r, AUG. TREADWELL, Jr. 

